Long-term outcomes after revascularization for advanced popliteal artery entrapment syndrome with segmental arterial occlusion

Long-term outcomes after revascularization for advanced popliteal artery entrapment syndrome with segmental arterial occlusion Seong-Yup Kim, MD, Seung-Kee Min, MD, PhD, Sanghyun Ahn, MD, Sang-Il Min, MD, Jongwon Ha, MD, PhD, and Sang Joon Kim, MD, PhD, Seoul, Korea Objectives: There are few long-term follow-up studies about the result of revascularization surgery for the treatment of popliteal artery entrapment syndrome (PAES). We performed this retrospective study to analyze the long-term result of revascularization surgery in patients with advanced PAES during the last 16 years. Methods: Twenty-two limbs in 18 consecutive patients with PAES were treated surgically at Seoul National University Hospital between January 1994 and December 2009. The preoperative diagnosis of PAES was made by duplex ultrasonography, three-dimensional computed tomography angiography, magnetic resonance imaging, or conventional angiography. The method of surgical approach was determined by the extent of arterial occlusion in preoperative images. Results: The mean age was 31 years old and the majority of patients were men (94%). The chief complaints were claudication in 18 limbs, ischemic rest pain in three limbs, and toe necrosis in one limb. All 22 limbs underwent revascularization for advanced PAES with segmental arterial occlusion. Fourteen limbs underwent musculotendinous section and popliteo-popliteal interposition graft (13 posterior approaches, one medial approach), five femoropopliteal (below-knee) bypasses, one femoro-posterior tibial bypass, and two popliteo-posterior tibial bypasses. All revascularization surgeries were performed with reversed saphenous veins. The overall primary graft patency rates at 1, 3, and 5 years were 80.9%, 74.6%, and 74.6%, respectively. Comparing 5-year graft patency according to the extent of arterial occlusion, patients with occlusion confined to the popliteal artery (n 14) showed a better patency rate than patients with occlusion extended beyond the popliteal artery (n 8) with no statistical significance (83.6% vs 53.6%; P.053). Comparing 5-year graft patency according to the inflow artery, superficial femoral artery inflow (n 6) showed a worse patency rate than popliteal artery inflow (n 16) (30.0% vs 85.9%; P.015). Conclusion: In advanced popliteal entrapment syndrome, longer bypass with superficial femoral artery inflow showed poor long-term graft patency rate. The graft patency rate was excellent in patients whose arterial occlusion was confined to the popliteal artery and treated by popliteal interposition graft with reversed saphenous vein. With these data, we suggest that longer bypass extending beyond the popliteal artery might only be indicated in patients with critical limb ischemia when the extent of disease does not allow short interposition graft. (J Vasc Surg 2012;55:90-7.) Popliteal artery entrapment syndrome (PAES) is caused by an anomalous relationship between the popliteal artery and its surrounding musculotendinous structures. It was first described by Stuart in 1879. Stuart observed the popliteal artery coursing around and deep to the medial head of the gastrocnemius muscle and resultant aneurysmal changes in the popliteal artery distal to the point of external compression. 1 The true incidence of the PAES in the general population is unknown. 2 Previously, many believed the condition to be rare, but it has recently become apparent that the condition is considerably more common than expected. 3 From the Department of Surgery, Seoul National University College of Medicine. Competition of interest: none. Reprint requests: Seung-Kee Min, MD, PhD, Department of Surgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 110 744, Republic of Korea (e-mail: skminmd@snuh.org). The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a competition of interest. 0741-5214/$36.00 Copyright 2012 by the Society for Vascular Surgery. doi:10.1016/j.jvs.2011.06.107 90 PAES is an important disease because it occurs more frequently in young active people and could be treated eminently with early diagnosis. The vast majority of reported cases have occurred in men, with over half affected before reaching 30 years of age. The principles of treatment are to release the entrapment and restore normal arterial flow. 4 A simple myotomy and release of the offending fibrous band could be an effective surgical procedure in the patients without arterial injury. However, in advanced cases with arterial damage, revascularization surgery is needed. Because the patients are mostly young active people, longterm patency of the revascularization procedures are warranted. But there are few long-term follow-up studies about the result of revascularization surgery in an advanced PAES. In our institution, most of the patients with PAES were diagnosed at an advanced stage and underwent revascularization surgeries. Herein, we performed a retrospective study to investigate the clinical course of PAES and the long-term result of revascularization surgery in advanced PAES during the last 16 years. METHODS Twenty-two limbs in 18 consecutive patients with PAES were treated surgically at Seoul National University

Volume 55, Number 1 Kim et al 91 Hospital between January 1994 and December 2009. The medical records of these patients were retrospectively reviewed, including demographic factors, clinical characteristics, diagnostic images, type of revascularization procedures, and their results. All limbs were affected by chronic ischemia and categorized into Rutherford categories based on symptoms and clinical presentation at the time of the revascularization. The preoperative diagnosis of PAES was made by duplex ultrasonography, three-dimensional computed tomography angiography (CTA), magnetic resonance imaging (MRI), or conventional angiography. The method of surgical approach was determined by preoperative clinical features. When the occluded segment extended up beyond the adductor canal or down to the popliteal trifurcation in preoperative images, a bypass surgery through a medial approach was preferred. Long-term follow-up data were collected to evaluate the patency rates. The graft patency was checked every 3 months during the first year and thereafter every 6 months by interviews, physical examination, hand-held Doppler scan, or duplex ultrasonography. If there were abnormal findings in noninvasive tests, CTA or digital subtraction angiography was performed to confirm the graft patency. Surgery-related risk factors for graft occlusion were compared, such as extent of arterial occlusion, inflow artery, and outflow artery. The extent of arterial occlusion was grouped into two groups: occlusion confined to the popliteal artery (group A) and occlusion extended beyond the popliteal artery (group B). The extended occlusion was defined that the occlusion extended to the superficial femoral artery (SFA) proximally or any tibial vessels distally. Arterial inflow was categorized as femoral or popliteal. All the femoral inflow was taken from the distal superficial femoral artery. The outflow artery was categorized as popliteal or tibial. The midcalf or distal posterior tibial artery was used as the tibial outflow. Data analysis was performed with SPSS software (version 17, SPSS, Chicago, Ill). Univariate analysis was obtained by either Fisher s exact test or the Mann-Whitney nonparametric rank-sum test. Cumulative patency rates were determined according to the Kaplan-Meier method. All values are expressed as mean SE. Significance was determined to be at P.05. RESULTS Demographics. A total of 22 limbs in 18 patients with PAES were treated surgically. The mean age was 31 2 years (median, 32 years; range, 17-45 years). Seventeen patients were men and one was a woman. The mean follow-up duration was 74.4 13.2 months (range, 1-207.9 months). The mean duration of symptoms before surgery was 33.8 11.6 months (median, 15 months; range, 1-240 months). Seven patients (39%) had bilateral involvement of entrapment by imaging studies. The symptoms of chronic ischemia related to PAES involved unilateral limbs in three cases among the patients with bilateral involvement. The chief complaint was claudication in 18 limbs, ischemic rest pain in three limbs, and toe necrosis in one limb. Thirteen patients (72.2%) were current or ex-smokers, one patient had well-controlled diabetes mellitus, and one patient had hypertension. Preoperative diagnosis and classification. For the preoperative evaluation, CTA was performed in 16 patients, conventional angiography in four patients, and MRI in six patients. The preoperative diagnostic modalities are listed in Table I. After adopting three-dimensional reconstruction technique, CTA became the main modality diagnostic tool after 2002. As most of our patients were young and healthy, they usually neglected the initial symptoms. In some cases, they were misdiagnosed as musculoskeletal disease and the initial diagnosis was delayed until they were presented to a vascular surgeon. All the patients were presented in advanced stage and had occluded arteries by the entrapment. Based on radiologic and operative findings, PAES was classified according to Delaney s classification 5 ; type I in five limbs, type II in 10 limbs, type III in five limbs, and type VI in two limbs (Table II). Type II was most common in this series (45%). Revascularization procedures. Bypass or interposition grafts with reversed saphenous vein were performed in 22 limbs. Fourteen limbs underwent musculotendinous section (MTS) and popliteo-popliteal interposition grafts, four femoropopliteal (below-knee [BK]) bypasses without MTS, one femoropopliteal (BK) bypass with MTS, one femoroposterior tibial bypass, and two popliteo-posterior tibial bypasses. Thirteen procedures were performed via a posterior approach and nine were via a medial approach. The limb whose arterial occlusion did not extend beyond the popliteal artery underwent MTS and popliteo-popliteal interposition graft and the posterior approach was preferred (Fig 1). The quality of the saphenous vein was assessed with preoperative duplex scan mapping. In cases of posterior approach, the great saphenous vein was harvested with the patient in the supine position and the position was changed to prone for MTS and revascularization, except one case using a small saphenous vein graft. All the femoral inflow was taken from distal SFAs. If the MTS was performed, the graft was tunneled via anatomic location. On the other hand, the graft was tunneled via subcutaneous tunnels without MTS. The vein graft was positioned to avoid acute angulation. The surgical procedure and Delaney s type of PAES are summarized in Table I. There was one case of functional entrapment (patient #1). He presented with toe necrosis with occluded right popliteal artery. There was no evidence of hypercoagulability, atherosclerosis, or other pathologic conditions. The operative findings showed no anatomic abnormality except for the bulky gastrocnemial muscles. Complications. There was no mortality or amputation. There was one patient with common peroneal nerve palsy. He had bilateral PAES, and right leg was treated by MTS and a popliteo-popliteal interposition graft with the posterior approach and his left leg by femoropopliteal bypass with a medial approach simultaneously. Right common peroneal nerve palsy was detected after the operation, which lasted more than 6 months despite supervised reha-

92 Kim et al January 2012 Table I. Summary of diagnosis and surgical treatment performed for popliteal artery entrapment syndrome Patient number Diagnostic Graft imaging Type Operated limb Surgical procedure a patency 1 CTA VI Bilateral, right POP (AK)-PTA bypass Occluded CTA VI Bilateral, left FEM-PTA bypass Occluded 2 CTA II Left MTS POP-POP interposition Patent 3 DSA, MRI II Right FEM-POP (BK) bypass Patent 4 DSA, MRI I Left MTS POP-POP interposition Patent 5 CTA, DSA III Right MTS FEM-POP (BK) bypass Occluded 6 CTA, MRI I Bilateral, right MTS POP-POP interposition Patent CTA, MRI II Bilateral, left MTS POP-POP interposition Patent 7 CTA, MRI III Left MTS POP-POP interposition Patent 8 CTA, MRI II Left MTS POP-POP interposition Patent 9 CTA I Bilateral, right MTS POP-POP interposition Patent CTA I Bilateral, left MTS POP-POP interposition Patent 10 CTA III Right MTS POP-POP interposition Occluded 11 CTA, MRI II Right MTS POP-POP interposition Patent 12 CTA II Bilateral, right MTS POP-POP interposition Patent CTA II Bilateral, left FEM-POP (BK) bypass Occluded 13 CTA II Left MTS POP-POP interposition Patent 14 CTA II Right MTS POP-POP interposition Patent 15 CTA, DSA III Left FEM-POP (BK) bypass Patent 16 CTA III Left POP (AK)-PTA bypass Patent 17 CTA II Left MTS POP-POP interposition Occluded 18 CTA I Right FEM-POP (BK) bypass Patent AK, Above knee; BK, below knee; CTA, computed tomography angiography; DSA, digital subtraction angiography; FEM, femoro; MRI, magnetic resonance imaging; MTS, musculotendinous section; POP, popliteal; POP-POP, popliteal (above-knee)-popliteal (below-knee); PTA, posterior tibial artery. a All of the bypasses or interpositions were performed with reversed saphenous vein graft. Table II. Classification of popliteal entrapment syndrome Type I Type II Type III Type IV Type V Type VI Medially displaced popliteal artery, normal MHG Normal popliteal artery, laterally displaced MHG Compression of popliteal artery by additional slip of gastrocnemius Compression of popliteal artery by popliteus Compression of popliteal vein with any type of popliteal artery entrapment Functional entrapment of popliteal artery, no aberrant anatomy MHG, Medial head of gastrocnemius. bilitation therapy. There was no cardiac event or wound problem. Overall graft patency. Overall primary graft patency rates at 1, 3, and 5 years were 80.9%, 74.6%, and 74.6%, respectively (Fig 2). Graft occlusion occurred in six limbs. Thrombolysis was tried in one limb, but failed. One patient underwent a new femoropopliteal bypass surgery. The others presented a few weeks after the recurrence of symptoms and were reluctant to aggressive revascularization procedures. Univariate analysis showed that smoking history, approach method (medial or posterior approach), Delaney s type of PAES, affected side, or the mean duration of symptoms before surgery did not influence the graft patency. Graft patency according to the extent of arterial occlusion. To analyze the difference according to the extent of arterial occlusion, we divided the treated limbs into two groups: occlusion that was confined to the popliteal artery (group A; n 14) and the occlusion that extended beyond the popliteal artery (group B; n 8). In group A, all the limbs underwent MTS and popliteo-popliteal interposition graft. There were 13 posterior approaches and one medial approach in group A. In group B, five patients underwent femoropopliteal (BK) bypass with or without MTS, one femoroposterior tibial bypass and two popliteo (above-knee [AK])-posterior tibial bypasses. All limbs in group B underwent a medial approach. In demographics, there were no significant differences between the two groups (Table III). Preoperative critical limb ischemia was present in one limb (7.0%) in group A and three limbs (37.5%) in group B. Preoperative symptom duration was 25.8 7.9 months in group A (median, 15 months; range, 1.0-96.0 months) and 46.9 28.1 months in group B (median, 25 months; range, 1.0-240 months) with no statistically significant difference (P.697). Graft occlusion developed in two limbs (14.3%) in group A and in four limbs (50.0%) in group B during the follow-up period, but there was no amputation after graft occlusion. The primary graft patency rates at 1, 3, and 5 years were 92.9%, 83.6%, 83.6% in group A, and 53.6%, 53.6%, 53.6% in group B (Fig 3). Although there was no statistically significant difference in the graft patency rate between group A and B (P.053), we found the trend of better graft patency rate in group A. Graft patency according to the inflow artery. To analyze the effect of the inflow artery used, we divided the treated limbs into two groups: SFA inflow (n 6) and popliteal (POP) artery inflow (n 16). There were no significant differences in demographics between the two

Volume 55, Number 1 Kim et al 93 Fig 1. Three-dimensional computed tomography angiography (CTA) shows popliteal entrapment syndrome (type I). A, Preoperative images; medial head of gastrocnemius muscle (arrowhead) deviates and occludes the popliteal artery (arrow). B, The follow-up images after musculotendinous section and popliteo-popliteal interposition graft show a patent vein graft. groups. Preoperative critical limb ischemia was present in two limbs (33.3%) in the SFA inflow group and two limbs (12.5%) in the POP inflow group. Graft occlusion developed in three patients (50%) of the SFA inflow group and in three (18.75%) of the POP inflow group. The primary graft patency rates at 1, 3, and 5 years were 93.8%, 85.9%, and 85.9% in the POP inflow group and 30.0%, 30.0%, and 30% in the SFA inflow group (Fig 4). The graft patency rate was significantly worse in the SFA inflow group (P.015). To rule out the effect of the outflow status, patients with good outflow (patent trifurcation) were selected: SFA inflow with POP (BK) outflow (n 5) and POP (AK) inflow with POP (BK) outflow (n 14). The 5-year patency rate was better in the POP (AK) inflow with the POP (BK) outflow group with no statistical significance (83.6% vs 37.5%; P.091). Graft patency according to outflow artery. To analyze the effect of the outflow artery used, we divided the treated limbs into two groups: POP outflow (n 19) and posterior tibial artery (PTA) outflow (n 3). Because the number of patients in the PTA outflow group was too small, there was no significant difference between the two groups. DISCUSSION PAES results from an abnormal anatomic relationship between the popliteal artery and its surrounding musculotendinous structures. 6 It can be classified into two categories: anatomic PAES and functional PAES. In anatomic PAES, muscular or tendinous aberrations are responsible for compression and injury of neurovascular structure. In functional PAES, the popliteal fossa anatomy seems nor-

94 Kim et al January 2012 Fig 2. Overall graft patency rate. Table III. Demographic factors and comorbidity according to the extent of arterial occlusion Group A a Group B b P value Age (years) 31 3 32 3.714 Sex (M:F) 13:1 8:0.636 Diabetes mellitus 2/14 0/8.667 Hypertension 0/14 1/8.364 Hyperlipidemia 0 0 NA Ischemic heart disease 0 0 NA Smoking 9/14 5/8.557 NA, Not applicable. a Group A, arterial occlusion confined to popliteal artery. b Group B, occlusion extended beyond popliteal artery. mal, and yet the popliteal arteries in the subset of patients will be compressed during leg movement. 7 Bilateral PAES are reported in 30% to 67% of patients. 8,9 In our study, seven patients (38.9%) had bilateral disease, which was diagnosed preoperatively. Six patients had anatomic PAES and one patient had functional PAES. In our series, only two of six patients with bilateral anatomic PAES underwent bilateral limb surgery at the same admission. As previously mentioned, earlier treatment usually offers better outcome in the treatment of anatomic PAES. However, four patients refused operations on the asymptomatic contralateral limbs. Eventually, two of these patients underwent surgery later because of the progression of ischemic symptoms in untreated limbs after 7 months and 3 years from the first operation. The remaining two patients had no symptoms during their 57- and 196-month follow-up period, and they still are reluctant to undergo the operation. Anatomic abnormalities tend to cause progressive degeneration and destruction of the vessel wall. 8 Myotomy of the medial head of the gastrocnemius muscle and excising abnormal tendinous bands is all that is needed if the artery seems normal. 10 Local repair of the popliteal artery or vein bypass to the BK popliteal or crural arteries is necessary if the artery has occlusive or aneurysmal changes. 6,11 Early surgical treatment that is limited to a musculotendinous section shows the best result. 4,12 In order to find out the risk factors for poor patency, we compared the patency according to the surgical approach method and disease extent. There were no differences between the medial approach and the posterior approach (P.11). However, limbs with confined disease in the popliteal artery showed better result than those with extended disease over the popliteal artery, although there was no statistically significant difference (5-year patency, 83.6% vs 53.6%; P.053). This might be due to the small number of patients. According to the inflow artery, the 5-year graft patency rate was significantly better in the popliteal inflow group than in the SFA inflow group (85.9% vs 30%; P.015). According to the outflow artery, the

Volume 55, Number 1 Kim et al 95 Fig 3. Primary patency rates according to the extent of arterial occlusion. Group A, arterial occlusion confined to popliteal artery; group B, occlusion extended beyond popliteal artery. POP outflow group and the PTA outflow group showed no differences. In brief, those with arterial occlusion extending beyond the popliteal artery usually need distal SFA inflow and longer bypass via a medial approach, which showed a tendency of poor long-term patency. Results from this study demonstrate the effectiveness and durability of a short-segment popliteal interposition graft with autologous vein when possible in the setting of PAES. However, when the extent of disease is such that longer segments of artery require bypass, the durability of such reconstructions can be expected to be relatively limited. This observation is especially relevant if bypass to a tibial level artery is required. If the extent of damage from PAES is such that a longer tibial bypass is required, results from this study suggest that the operation should only be done for critical limb ischemia. To our knowledge, there were no long-term follow-up studies comparing the patency rates between popliteopopliteal interposition graft and longer bypass. However, we could find out indirect evidence supporting our suggestion. The study by di Marzo et al 13 reported that a vascular reconstruction was required when PAES was diagnosed at a late stage. In this study, 29 limbs which underwent only MTS had a better long-term patency rate (95% at a mean follow-up of 87 7 months) compared with 15 limbs that underwent vascular reconstruction (65% at a mean follow-up of 107 8 months; P.01). Levien et al 3 described a case series of 66 limbs that underwent MTS and 16 limbs that underwent segmental replacement of the occluded popliteal artery with reversed saphenous vein. All the limbs of the MTS group remained with a healthy and patent popliteal artery during the follow-up period (median, 3.9 years). The limbs treated with popliteo-popliteal interposition graft showed no occlusion (median followup, 4.2 years). Comparing these two reports, it can be presumed that the worse results of the series by di Marzo et al 12,13 were due to the mixed vascular reconstruction procedures, including popliteo-popliteal interposition graft (n 9) and other longer bypass surgery (n 6). In contrast, vascular reconstruction in the series by Levien et al 2,3 was composed of only popliteal artery interposition graft with reversed saphenous vein. Another treatment option could be endovascular therapy, including thrombolysis. Steurer et al 14 reported three cases that were successfully treated by combined strategy; initial endovascular therapy, followed by surgical correction of the anomalous tendomuscular structures at a later date. Endovascular therapy included catheter-directed thrombolysis, percutaneous thromboembolectomy, and percutaneous transluminal angioplasty when necessary. The advan-

96 Kim et al January 2012 Fig 4. Kaplan-Meier curves show the primary patency rates according to the inflow artery. The popliteal artery inflow group shows a better patency rate than the superficial femoral artery inflow group. PA, Popliteal artery; SFA, superficial femoral artery. tage of this combined therapy is that it avoids venous bypass in these young patients or it can shorten the length of the revascularization procedure. As our data tell that shorter revascularization is better, we now consider the endovascular therapy as a kind of a neoadjuvant therapy to downgrade the length of revascularization procedures. Unfortunately, during the study period, we had no patient who presented earlier and performed MTS only. All the patients were in advanced stage with segmental arterial occlusion. Thrombolysis was not tried due to the delayed presentation. In the series by di Marzo et al, 12,13 the mean duration of symptoms was 21 2 months in the MTS group. In our series, it was 33 12 months. As PAES progresses, if the offending mechanism is not resolved, the longer preoperative symptom duration results in a higher rate of popliteal arterial damage. In our series, preoperative symptom duration was more than 1 year in 12 patients. Ten of them neglected initial symptoms and two of them were treated as having a muscular sprain by primary physicians. We might assume that longer arterial occlusion may be related to longer preoperative symptom duration and worse surgical outcome. Education programs for patients and primary physicians are all needed to promote early detection of the disease. Our study has some limitations. First, there was no patient who underwent only MTS or adjunctive thrombolysis, so all the subsets of treatment methods for PAES could not be analyzed. This is mainly due to the late presentation and diagnosis in our cases. As patients with PAES are young, they usually neglected initial leg pain or were frequently misinformed of having a muscular sprain by primary care givers. A high suspicion and early referral to a vascular surgeon is important for the early diagnosis and treatment of PAES in young patients. Second, the enrolled case number is too small to draw any statistically significant comparison. As PAES is not a common disease, it is difficult to collect enough cases. Multicenter prospective data collection is required. CONCLUSIONS In advanced popliteal entrapment syndrome with segmental arterial occlusion, longer bypass with SFA inflow or tibial outflow showed poor long-term graft patency rate. The graft patency rate was excellent in patients whose arterial occlusion was confined to the popliteal artery and treated by popliteo-popliteal interposition graft with reversed saphenous vein. With these data, we suggest that longer bypass with SFA inflow or tibial outflow might only

Volume 55, Number 1 Kim et al 97 be indicated in patients with critical limb ischemia when the extent of disease does not allow shorter interposition graft. AUTHOR CONTRIBUTIONS Conception and design: SKM, SJK Analysis and interpretation: SYK, SKM Data collection: SYK, SA, SIM Writing the article: SYK Critical revision of the article: SKM Final approval of the article: SKM, JH, SJK Statistical analysis: SYK, SKM Obtained funding: Not applicable Overall responsibility: SKM REFERENCES 1. Stuart TP. Note on a variation in the course of the popliteal artery. J Anat Physiol 1879;13(Pt 2):162. 2. Levien LJ. Popliteal artery entrapment syndrome. Semin Vasc Surg 2003;16:223-31. 3. Levien LJ, Veller MG. Popliteal artery entrapment syndrome: more common than previously recognized. J Vasc Surg 1999;30:587-98. 4. Stager A, Clement D. Popliteal artery entrapment syndrome. Sports Med 1999;28:61-70. 5. Delaney TA, Gonzalez LL. Occlusion of popliteal artery due to muscular entrapment. Surgery 1971;69:97-101. 6. Noorani A, Walsh SR, Cooper DG, Varty K. Entrapment syndromes. Eur J Vasc Endovasc Surg 2009;37:213-20. 7. Pillai J. A current interpretation of popliteal vascular entrapment. J Vasc Surg 2008;48(6 Suppl):61S-5S; discussion 65S. 8. Murray A, Halliday M, Croft RJ. Popliteal artery entrapment syndrome. Br J Surg 1991;78:1414-9. 9. Collins PS, McDonald PT, Lim RC. Popliteal artery entrapment: an evolving syndrome. J Vasc Surg 1989;10:484-9; discussion 489-90. 10. Ohara N, Miyata T, Oshiro H, Shigematsu H. Surgical treatment for popliteal artery entrapment syndrome. Cardiovasc Surg 2001;9:141-4. 11. Turnipseed WD. Popliteal entrapment syndrome. J Vasc Surg 2002;35: 910-5. 12. di Marzo L, Cavallaro A, Sciacca V, Mingoli A, Stipa S. Natural history of entrapment of the popliteal artery. J Am Coll Surg 1994;178:553-6. 13. di Marzo L, Cavallaro A, Mingoli A, Sapienza P, Tedesco M, Stipa S. Popliteal artery entrapment syndrome: the role of early diagnosis and treatment. Surgery 1997;122:26-31. 14. Steurer J, Hoffmann U, Schneider E, Largiader J, Bollinger A. A new therapeutic approach to popliteal artery entrapment syndrome (PAES). Eur J Vasc Endovasc Surg 1995;10:243-7. Submitted Apr 20, 2011; accepted Jun 20, 2011.